This invention relates to semiconductor device mounting and more specifically relates to a novel housing for a high current press-fit diode which enables its mounting into the top surface or bottom surface of an opening in a flat conductive support body.
Press-fit diodes are well-known for high current applications, such as for welders using diodes rated, typically at about 50 amperes. These devices typically have a cylindrical conductive housing with a knurl on their outer diameter and having A coaxial power lead extending from one end to the cylindrical body and insulated therefrom.
A semiconductor die, typically a diode, is suitably mounted within the housing and has one die electrode connected to and supported on the bottom interior of the conductive cylindrical housing, while the other die electrode, on the opposite surface of the die, is connected to the insulated power lead.
The device is mounted by being forced into a thru-opening in a conductive bar so that the exterior cylindrical housing is electrically connected to the conductive bar while the axially extending lead extends away from the plane of the conductive bar and is insulated therefrom.
Press-fit diodes of the prior art are designed so that they can be forced into the thru-opening in the bus bar (or conductive support) with either the bottom of the housing, or the opposite end thereof in a leading direction. That is, they can be forced into the top of the hole in the conductor or into the bottom thereof, respectively. The diode housing has a structure which is tailored to being forced from either the bottom or the top of the conductor. Thus, those which are to be mounted from the bottom of the bus (an arbitrary designation referring to the interior of the diode in such a direction that the axial lead first moves through the hole) have a general taper which narrows from the housing bottom to its top, enabling a force fit into the opening by pressing against the rigid bottom conductive body of the cylindrical housing. However, devices which are to be mounted from the top have a generally right cylindrical wall terminating in a flange, and are mounted by applying downward pressure to the flange to force its housing bottom and tubular wall into high pressure contact with the hole.
The present devices cannot be interchangeably used since the flange of the top mounted device prevents bottom mounting and the taper of the bottom mount device prevents top mounting.
It would be desirable to have a single press fit device which can be both top and bottom mounted.
In accordance with the invention, a novel housing structure is provided for a press-fit semiconductor device in which the semiconductor housing body has a flat bottom and a right cylindrical wall which terminates on a top surface. The top surface contains an insulation disk and an outer peripheral edge surface of the cylindrical wall which defines a pressing surface. The axially extending lead extends through the insulation disk. The top and bottom edges of the cylindrical wall are then rounded or tapered so that either the top or bottom of the housing can be located at the bottom or top surface respectively of a hole in conductive mounting bar which is to receive the device. Pressure can then be applied to either the bottom of the housing or at upper peripheral edge portion so that it can be forced fully into the hole.
Thus, the single device can be used for both top mounting and bottom mounting within a bus bar.